In solid tumors, regulatory T cell (Treg) and mast cell perform different roles depending on the microenvironment. Nevertheless, mast cell and Treg-mediated interactions in gastric cancer (GC) are unclear, as are their regulation, function, and clinical significance. The present study demonstrated the mechanism of tumor-infiltrating mast cells stimulating ICOS⁺ regulatory T cells via the IL-33/IL-2 axis to promote the growth of gastric cancer. Analyses of 98 patients with GC were conducted to examine mast cell counts, ICOS⁺ Tregs, and the levels of IL-33 or IL-2. Isolated ICOS⁺ Treg and CD8⁺ T cell were stimulated, cultured and tested for their functional abilities in vitro and in vivo. GC patients exhibited a significantly more production of IL-33 in tumors. Mast cell stimulated by tumor-derived IL-33 exhibited a prolonged lifespan through IL-33 mediated inhibition of apoptosis. Moreover, mast cells stimulated by tumor-derived IL-33 secreted IL-2, which induced Treg expansion. These inducible Tregs displayed an activated immunosuppressive phenotype with positive expression for the inducible T cell co-stimulator (ICOS). In vitro, IL-2 from IL to 33-stimulated mast cells induced increased numbers of ICOS⁺ Tregs with increased immunosuppressive activity against proliferation and effector function of CD8⁺ T cell. In vivo, ICOS⁺ Tregs were treated with anti-IL-2 neutralizing antibody followed by co-injection with CD8⁺ T cells in GC mouse model, which showed an increased CD8⁺ T cell infiltration and effector molecules production, meanwhile tumor growth and progression were inhibited. Besides, reduction in GC patient survival was associated with tumor-derived ICOS⁺ Tregs. Our results highlight a crosstalk between GC-infiltrating mast cells and ICOS⁺ Tregs and provide a novel mechanism describing ICOS⁺ Treg expansion and induction by an IL-33/mast cell/IL-2 signaling axis in GC, and also provide functional evidence that the modulation of this immunosuppressive pathway can attenuate GC-mediated immune tolerance.

Arrestin domain containing 3 (ARRDC3) represents a newly discovered α-arrestin involved in obesity, inflammation, and cancer. Here, we demonstrate a proinflammation role of ARRDC3 in Helicobacter pylori –associated gastritis. Increased ARRDC3 was detected in gastric mucosa of patients and mice infected with H . pylori . ARRDC3 in gastric epithelial cells (GECs) was induced by H . pylori , regulated by ERK and PI3K-AKT pathways in a cagA -dependent manner. Human gastric ARRDC3 correlated with the severity of gastritis, and mouse ARRDC3 from non-BM–derived cells promoted gastric inflammation. This inflammation was characterized by the CXCR2-dependent influx of CD45 ⁺ CD11b ⁺ Ly6C ^– Ly6G ⁺ neutrophils, whose migration was induced via the ARRDC3-dependent production of CXCL2 by GECs. Importantly, gastric inflammation was attenuated in Arrdc3 ^–/– mice but increased in protease-activated receptor 1 ^–/– ( Par1 ^–/– ) mice. Mechanistically, ARRDC3 in GECs directly interacted with PAR1 and negatively regulated PAR1 via ARRDC3-mediated lysosomal degradation, which abrogated the suppression of CXCL2 production and following neutrophil chemotaxis by PAR1, thereby contributing to the development of H . pylori –associated gastritis. This study identifies a regulatory network involving H . pylori , GECs, ARRDC3, PAR1, and neutrophils, which collectively exert a proinflammatory effect within the gastric microenvironment. Efforts to inhibit this ARRDC3-dependent pathway may provide valuable strategies in treating of H . pylori –associated gastritis.

Background: Crohn’s disease (CD) is a complex and heterogeneous inflammatory disease whose most important feature is immune dysregulation. As a basic cell response, cellular senescence (CS) can regulate the immune response involved in a variety of inflammatory diseases. However, the role of CS in the pathogenesis and diagnosis prediction of CD are still unknown.Methods: We utilized CD-related datasets from the GEO database for differential gene expression analysis, and CS related differentially expressed genes (CSRDEGs) in CD by a comprehensive bioinformatics analysis encompassing GSEA, WGCNA, and various interaction networks. The support vector machine (SVM) algorithm, random forest algorithm and LASSO regression analysis was used to construct a diagnostic model. And based on CSRDEGs, we further constructed a Cellular senescence score (CSscore) model. Different disease subtypes (cluster1/cluster2) were identified by the consensus clustering method. The assessment of immune cell infiltration and its correlation with CSRDEGs was analyzed by ssGAEA and CIBERSORT.Results: We identified 10 hub CS related differentially expressed genes (CSRDEGs) in CD. Based on CSRDEGs, we further constructed a diagnostic model (AUC = 0.880) containing 5 CSRDEGs (CDKN1A, IL1A, PML, SIRT1, and STAT3) through machine learning algorithm and other methods and analyzed the correlation with immune cell infiltration. In addition, a CS Scores model (Low or High) based on the 7 CSRDEGs (CDKN2B, IGFBP7, IL1A, IL6, PML, SIRT1, and STAT3) shows different characteristics, reaffirming the inflammatory regulatory role of CS in CD. Finally, the subtype construction (cluster1 and cluster2) based on 10 CSRDEGs shows the heterogeneity of the disease and affirms that CS is a prominent feature of CD.Conclusions: These results suggest that CS is an important feature of CD, and CSRDEGs can be used to construct disease diagnostic models and distinguish disease subtypes. Further investigation of the mechanism of immune dysregulation caused by CS can deepen our understanding of the pathogenesis of CD.

Bacteria-modulated gastric epithelial cells (GECs) play key roles in Helicobacter pylori –associated pathology. Here, we demonstrate both procolonization and proinflammation roles of GEC-derived PPFIA4 in H . pylori infection. PPFIA4 was elevated in GECs from gastric mucosa of H . pylori –infected patients and mice. PPFIA4 could be synergistically induced by H . pylori and IL-33 via the CagA/AP1 pathway. Human gastric PPFIA4 correlated with H . pylori colonization and the severity of gastritis, and H . pylori colonization and inflammation were attenuated in Ppfia4 ^ΔGEC mice. Mechanistically, PPFIA4’s SAM1 domain bound domains from CaMK to the first L27 of CASK and subsequently formed a PPFIA4/CASK/AKT1 complex to activate AKT1, resulting in NF-κB activation and MMP1/CXCL3 secretion. This not only led to decreased E-cadherin and ZO-1 by MMP1, thereby promoting gastric mucosal damage to foster H . pylori colonization, but also resulted in increased gastric influx of G-MDSCs via CXCL3-dependent migration, thereby promoting gastritis and impairing H . pylori –specific IFN-γ–producing CD4 ⁺ T cell responses to foster H . pylori colonization. Furthermore, we identified a PPFIA4 inhibitor, kira6, which effectively inhibited GEC’s MMP1/CXCL3 production and ameliorated gastric H . pylori colonization and gastritis. Overall, PPFIA4 could be a promising therapeutic target, as it collectively ensures H . pylori persistence and promotes gastritis.

Helicobacter pylori (H. pylori) associated gastritis, marked by chronic gastric inflammation, heightens gastric cancer risk by fostering a malignancy-prone microenvironment. Disruption of the biorhythm contribute to the onset of various gastrointestinal disorders, such as gastric dyspepsia, gastric ulcers, and cancer. We aimed to investigate the functional roles and regulatory mechanisms of key biorhythm molecules in H. pylori associated gastritis. We investigated biorhythm gene expression in H. pylori-infected human gastric tissues and found significant impact on NFIL3 expression. Animal studies confirmed that H. pylori controls NFIL3 biorhythm. Clinical samples indicated a correlation between NFIL3 and gastritis severity, suggesting a regulatory role. Then, we found that H. pylori disrupt NFIL3 expression rhythm in gastric epithelial cells (GECs) through the CagA-activated ERK-SP1 pathway. Additionally, cytokines IL1β and TNFα enhance this disruption. RNA-seq and Gene set enrichment analysis (GSEA) indicated that NFIL3 positively regulates the inflammatory response during H. pylori infection. Our research highlights the crucial role of the biorhythm molecule NFIL3 in H. pylori associated gastritis. Modulating biorhythm molecules could be a promising therapeutic approach to manage disease progression, given their impact on gastrointestinal pathology.

Actin cytoskeleton dynamic rearrangement is required for tumor cell metastasis and is a key characteristic of Helicobacter pylori (H. pylori)-infected host cells. Actin cytoskeleton modulation is coordinated by multiple actin-binding proteins (ABP). Through Kyoto encyclopedia of gene and genomes database, GEPIA website, and real-time PCR data, we found that H. pylori infection significantly induced L-plastin, a key ABP, in gastric cancer cells. We further explored the regulation and function of L-plastin in H. pylori–associated gastric cancer and found that, mechanistically, H. pylori infection induced gastric cancer cells to express L-plastin via cagA-activated ERK signaling pathway to mediate SP1 binding to L-plastin promoter. Moreover, this increased L-plastin promoted gastric cancer cell proliferation and migration in vitro and facilitated the growth and metastasis of gastric cancer in vivo. Finally, we detected the expression pattern of L-plastin in gastric cancer tissues, and found that L-plastin was increased in gastric cancer tissues and that this increase of L-plastin positively correlated with cagA+ H. pylori infection status. Overall, our results elucidate a novel mechanism of L-plastin expression induced by H. pylori, and a new function of L-plastin–facilitated growth and metastasis of gastric cancer, and thereby implicating L-plastin as a potential therapeutic target against gastric cancer.Implications:Our results elucidate a novel mechanism of L-plastin expression induced by H. pylori in gastric cancer, and a new function of L-plastin–facilitated gastric cancer growth and metastasis, implicating L-plastin as a potential therapeutic target against gastric cancer.